Epidural steroid injections (ESIs) are a common treatment option for many forms of lower back pain and leg pain. They have been used for decades and are considered an integral part of the nonsurgical management of sciatica and lower back pain.
The injection is named an epidural steroid injection because it involves injecting a local anesthetic and a steroid medication directly into the epidural space that surrounds the spinal cord and nerve roots.1
The goals of an epidural steroid injection are to:
- Control pain by reducing inflammation in and around the nerve roots
- Improve mobility and function in the lower back and legs1
- Allow the patient to participate in and make progress with a comprehensive physical therapy and rehabilitation program
In the course of one’s care program, in most cases, an epidural steroid injection may be recommended after a series of nonsurgical treatments, such as medications and physical therapy,2 have been tried, and before surgery is considered.
The role of the injection is typically to provide sufficient pain relief to allow a return to everyday activities and to make progress in physical therapy.
This article includes extensive research and information about how epidural injections may be used to treat lower back problems and sciatica.
Potential Benefits of Epidural Steroid Injections
Most practitioners will agree that an epidural injection can be beneficial during an acute episode of back and/or leg pain. The main drawbacks of the injections are that they are not always effective, and when effective, the pain relief tends to be temporary, ranging from one week to one year. Typically, if the initial injection is effective, up to 3 injections may be given in one year.
When administered in the lumbar epidural space, steroid injections may have the following benefits:
- Reduce nerve pain and inflammation. Steroids decrease the production of inflammatory chemicals and reduce the sensitivity of nerve fibers to pain, generating fewer pain signals.3,4
- Limit oral medication. Pain relief from these injections may help limit or eliminate the need for oral medications,4 some of which may have side effects when taken long-term.
- Continue or re-engage in physical therapy. This injection may provide sufficient pain relief to allow a patient to progress with a rehabilitative physical therapy program.1
- Postpone surgery. Pain relief experienced from lumbar epidural steroid injections may help postpone surgery, and if physical therapy is effective, it may eliminate the need for surgical intervention.4,5
Several techniques may be used to administer an epidural injection depending on underlying the condition, the patient’s needs, and the doctor’s preference and experience.
Epidural Injection Approaches
This type of injection can provide acute and significant pain relief because it introduces a steroid medication with strong anti-inflammatory effects directly into the painful area near the spinal nerve(s). An epidural injection may be given using any one of the following approaches:
- Transforaminal route: This technique allows precise administration of the steroid solution into the epidural space, near the area where the nerve is likely to be irritated. This injection technique targets specific nerve roots to control inflammation and pain.1,6
- Interlaminar route: In this technique, the needle is inserted from the back of the spine and the medication is deposited into the epidural space. This method is less precise because it does not deposit the medication near the target nerve root, and the steroid solution is free to spread within the epidural space.1,7
- Caudal route: This is a general approach is simple to administer, but medication doesn’t go directly to the source of the pain in the epidural space and around the nerves. The caudal approach may be less effective but is considered safer and easier to perform. This method may help control widespread or diffused pain.3,7
A doctor may choose the route of administration depending on their experience and skill, the use of guided fluoroscopy, the patient’s diagnosis, and the results from previous treatments for similar symptoms and diagnoses.
Effectiveness of Injections
Available research indicates generally favorable results, with 70% to 90% of patients experiencing pain relief from these injections, lasting for a week to a year.1,8 If a good first response is seen, a second injection may be considered when the improvement from the first injection begins to taper off. Typically, up to 3 injections may be given over a 12-month period.1,6
While many studies have documented the short-term benefits of epidural steroid injections, the data on long-term effectiveness are less convincing. Controversy persists regarding their effectiveness in reducing pain and improving the function. Literature both supporting and opposing them are available.6
In addition, there are several limitations in the research that has been conducted, such as:
- Many studies do not include the use of fluoroscopy or x-ray to verify the proper placement of the medication despite the fact that fluoroscopic guidance is routinely used today.
- Other studies do not classify patients according to diagnosis and tend to 'lump' different types of pain sources together.
These methodological flaws tend to limit the usefulness of the research. More studies are needed to define the role of epidural steroid injections in lower back pain and sciatica.
When Epidural Steroid Injections May be Used
Lumbar epidural injections are typically used in the treatment of conditions that cause irritation and/or inflammation of spinal nerve roots with associated lower back and leg pain. Most common lower back conditions treated include1:
Who Performs the Injections
Doctors who administer this type of injection include spine and pain management specialists, such as physiatrists, anesthesiologists, radiologists, neurologists, and spine surgeons. The injection procedure typically takes place in a surgery center, hospital, or a physician's clinic.
Potential Risks and Contraindications for Epidural Injections
Epidural steroid injections are considered a relatively safe and minimally invasive. Temporary side effects may occur in some cases and include (but are not limited to):
- Post-injection pain
- Fainting (vasovagal attack)
- Flushing of the face
Lower risk at spinal levels L4 and below
In general, epidural injections administered for spinal levels L4 or lower carry a lesser risk of complication(s) compared to higher levels.10,11 The injections are typically performed under fluoroscopy (x-ray guidance) with a contrast dye. Fluoroscopy helps guide the needle to the accurate location and helps prevent nerve and/or artery damage.1
Specific concomitant medical conditions may raise risk
The injections are typically not given when certain complicating medical conditions are present, such as infections, tumors, or bleeding disorders. Additionally, the injections may not be given in case of uncontrolled diabetes mellitus, certain heart conditions, and pregnancy.1
Sedatives and/or anesthetic may be used
If necessary, a relaxation medication may be given through an intravenous (IV) line in the patient’s arm, but the patient is usually conscious during this procedure. The treatment area in the lower back is numbed with a local anesthetic injection before the epidural is given, so the epidural injection procedure is usually painless.
An epidural steroid injection procedure may take about 30 minutes to administer. A tingling or mild burning sensation, or the feeling of pressure may be experienced as the medication enters the epidural space. When the injection is completed, the irritation and discomfort usually disappear within a few minutes. Patients typically return home after a few hours. Specific post-injection precautions are followed over the next few days.